Tuning-pin.



J. HEGIN BOTHOM.

TUNING PIN.

APPLIUATIOH TILED JULY 22, 1908.

903,086. Patented Nov. a, 1908.

rm! Moll! Pl1lll ca. IAulumnII. D. c,

UNITED STATES PATENT OFFICE.

JOSEPH HEGINBOTHOM, OF PHILADELPHIA, PENNSYLVANIA.

TUNING-PIN.

To all whom it may concern:

Be it known that I, J OSEPH HEGINBOTHOM, a citizen of the United States, residing in Philadel hia, Pennsylvania, have invented certain mprovements in Tuning Pins, of which the following is a specification.

The object of my invention is to so construct a tuning pin for pianos, harps, and like stringed musical instruments as to prevent loosenin of the in due to the shrinking of the woo of which the pin-block or like pinreceiving member of the instrument is usually composed. This object I attain in the manner hereinafter set forth, reference being had to the accompanying drawing, in which Figure 1 represents a side elevation, on an enlarged scale, of a tuning pin constructed in accordance with my invention, and Fig. 2 represents another form of tuning pin also embodying my invention.

The ordinary tunin pin of a piano is a solid pin of iron or stedl of uniform diameter throughout except as to the tapered oint and s uared and tapered head, the pin eing threa ed externally throughout the greater portion of its length and being screwed into an openin in the pin-block of the piano. As the threa out upon the pin is usuall very fine the slightest shrinkage in the wood of the pin-block permits the pin to back off, thereby etting down the tension upon the wire which it controls and putting said wire out of tune. In order to overcome this objection I rovide the tunin pin with a central vertica slot 1, thereby dividing the threaded portion of the pin into opposite resilient members 2, 2, whereby, when the pin is screwed into the in-block, the threaded members will be orced together and the slot will be closed or partially closed, each member, therefore,

aving a constant tendency to s ring out ward and resume its normal position, which tendency causes it to follow any expansion in diameter of the opening in the pin-block due to shrinkage of the wood of which the same is composed, the result bein that the threads of the pin are kept in cfose enga ement with the threads on the interior of t e opening in the pin-block and the backing off 0 the pin by the strain of the wire thereupon is revente 11 order to increase the outward thrust of the side members of the pin, each of the same is slightly swelled or expanded between its upper and lower ends as shown in Fig. 1, the

Specification of Letters Patent.

Application filed Julyt22, 1908.

Patented Nov. 3, 1908.

Serial No. 444,855.

greatest swell being preferabl about midway of the threaded portion of t e in, because, when thus located, contact of t e two members of the pin, when external pressure is applied thereto, begins at the lower end or point of the pin and gradually proceeds upwardly until the point of greatest ex ansion is reached, and this insures the best old of the pin upon the pin-block without detracting from the desired elasticit of the members of the pin, which implies t e extension of the slot therein for some distance above the point of maximum swell or expansion.

The pin is, by reference, first threaded, then slotted and t 1en spread or expanded so as to impart alike spread or expansion to the slot, as shown in Fig. 1, but the swell or expansion of the members of the pin may be due to the initial conformation of the same, the slot bein of uniform width throughout as shown in ig. 2. The swell or expansion may be limited to one member of the pin if desired, although it is preferable to swell or expand both members of the pin in the manner described.

I am aware that an ordinary tapered Wooden tuning pin or eg has been slotted longitudinally and the s ot filled with rubber or other elastic material, but my invention differs from that referred to, in that the in is of metal, is externally threaded, an is without any distending agency other than the resiliency of the members of the pin, moreover, the prior tuning pin or peg referred to lacked the swell or expansion of the side members of the same whlch is an important feature of my invention.

I claim:

1. A metal tuning pin threaded externally and having a central longitudinal slot, whereby the pin presents opposite resilient members.

2. A metal tuning pin threaded externally, slotted longitudinally, and having a lateral swell in either of the members thus formed.

3. A metal tuning in, threaded externally, slotted longitudinally, and havin a lateral swell in each of the members t us formed.

4. A metal tuning pin, threaded externally, slotted lon itudinally, and having a lateral swell in eit er of the members of the pin thus formed, as well as in the slot.

5. A metal tuning pin, threaded externally, slotted longitudinally, and having a lateral swell in each of the members of the pin thus formed, as well as in the slot.

6. A metal tuning pin threaded externally, slotted longitudinally, and having, in. either of the members of the pin thereby formed, a lateral swell which is reatest about midway of the length of the s 0t.

7. A metal tuning pin threaded externally, slotted longitudinally, and having, in each of the members of the pin thereby formed, a lateral swell which is greatest about midway of the length of the slot.

8. A metal tuning pin threaded externally, slotted longitudinally, and having, in

said slot and in either member of the pin, a lateral swell which is reatest about midway of the length of the sit.

9. A metal tuning pin threaded externally slotted longitudinally, and having, in said slot and in each member of the in, a lateral swell which is greatest about mldway of the length of the slot.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

JOSEPH HEGINBOTHOM.

Witnesses:

HAMILTON D. TURNER, KATE A. BEADLE. 

